1. Field of the Invention
This invention relates to a power transmission chain, and more particularly to a power transmission chain and a power transmission apparatus suited for a continuously variable transmission (CVT) of a vehicle such as an automobile.
2. Related Art
As a continuously variable transmission for an automobile, there is known the type (as shown in FIG. 5) which comprises a driving pulley 2 having a fixed sheave 2a and a movable sheave 2b and operatively connected to an engine, a driven pulley 3 having a fixed sheave 3b and a movable sheave 3a and operatively connected to a drive wheel, and an endless power transmission chain 1 extending around the two pulleys. Each movable sheave 2b, 3a is moved toward and away from the corresponding fixed sheave 2a, 3b by a hydraulic actuator, and by doing so, the chain 1 is clamped by hydraulic pressure, and by this clamping force, a contact load is caused to develop between each pulley 2, 3 and the chain 1, and a torque is transmitted by a frictional force of this contact portion.
In JP-A-2005-233275 Publication, there is proposed a power transmission chain which comprises a plurality of links having front and rear insertion through holes for the passage of pins therethrough, and a plurality of first pins and a plurality of second pins which are arranged on front and rear sides to interconnect the links arranged in a width of the chain in such a manner that the front insertion through hole of one link corresponds to the rear insertion through hole of other link. The first pins and the second pins move relatively in rolling contact with each other so that the links can be bent relative to each other in a chain length direction. One of the first pin and the second pin is fixedly fitted in the front insertion through hole of one link and movably fitted in the rear insertion through hole of the other link and the other of the first pin and the second pin is movably fitted in the front insertion through hole of the one link and fixedly fitted in the rear insertion through hole of the other link.
According to the power transmission chain shown in JP-A-2005-233275 Publication, it is preferable that a gap is formed between adjacent links arranged in the chain width direction, because if no gap is formed between the adjacent links, the links tend to be worn due to friction force caused by contact between the adjacent links. However, if the chain is configured in such a manner, a problem has been often caused that vibration and noise are increased in the chain, since the friction force between the adjacent links is not generated which serves as deterrent force when string vibration is generated in the chain.